Multifocal lenses are known from U.S. Pat. No. 6,536,899. In the multifocal lenses there, it is provided that annular zones completely encircling the main optical axis are formed. Each zone has a main sub-zone and a phase sub-zone. A phase deviation is formed between two zones adjacent in radial direction. The zones have identical areas and an optical step is not formed between adjacent zones, which means that the surface configuration is continuous. In particular, this also means that a wave front behind the lens is continuous, that is that optical path length differences or optical steps do not occur between partial areas of the wave front behind the lens.
Interference problems, as they are also explained in the prior art, can be encountered by the phase sub-zones. Here, phase shifts between partial waves from different areas or zones of the lens, in which the phase shifts are requirements for multifocality of the lens, are not caused by optical steps as usual in diffractive lenses, but by these phase sub-zones with specific refractive power. Such a configuration and a corresponding construction of a lens with this division of annular zones into a main sub-zone and a phase sub-zone therefore present a basically different approach.
Moreover, from U.S. Pat. No. 9,223,148, a further configuration of a multifocal lens is known, in which the principle of the annular zones, of which zones have a main sub-zone and a phase sub-zone, is also shown.
As indicated in the prior art, the following relation applies to an averaged refractive power of the lens:FAV=(1−p)FG+pFS  (1)wherein it applies therein that FAV is precisely the averaged refractive power, FG is a refractive power of a main sub-zone of a considered zone, FS is the refractive power in the phase sub-zone of this zone and p is the area portion of the main sub-zone of the entire zone.
Furthermore, the difference ΔF between the greater refractive power F2 (near refractive power) and the smaller refractive power F1 (far refractive power) also results from the addition refractive power of the at least bifocal lens formed of annular zones with respectively at least one main sub-zone and at least one phase zone as
                              Δ          ⁢                                          ⁢          F                =                              λ            ⁢                                                  ⁢            N                                B            2                                              (        2        )            
In this formula 2, λ is the configuration wavelength, which can for example be between 540 and 560 nm, for example 546 nm. N is the number of the annular zones, and B is the diameter of the lens, on which the annular zones are located, and thus in particular the diameter of the optical part of the lens.
These known multifocal lenses have very good imaging characteristics.
From U.S. Pat. No. 8,465,543, an astigmatic intraocular lens is known, which therefore has a toric refractive lens surface.
Due to its relatively complex construction and thus in particular also the parts provided for optical imaging and/or other influencing factors, the human eye can be afflicted with very different visual defects. They can be individually differently pronounced in the intensity, on the other hand, a plurality of different visual defects can also be present in an eye.
In order to be able to at least substantially improve this visual defect complexity, it is a constant effort to further develop eye lenses to that effect. Especially in intraocular lenses, in this context, also with respect to the handling in a surgical procedure, the small incision capability and thus the introduction of a correspondingly folded intraocular lens through an incision in the eye as small as possible as well as the compactness of such a lens are also essential aspects, which are to be taken into account.
Considering all of these requirements, thus, corresponding operability requirements also have to be satisfied besides a plurality of optical requirements partly difficult to be dealt with.